1. Field of the Invention
The instant disclosure relates to an antenna; in particular, to a multi-band antenna.
2. Description of Related Art
Please refer to FIG. 1A in conjunction with FIG. 1B, FIG. 1A shows a schematic diagram of a conventional penta-band antenna installed to a mobile communication device, FIG. 1B shows a schematic diagram of a conventional penta-band antenna. A mobile communication device 1 may be a smart phone for example. The mobile communication device 1 comprises casings 11 and 12, a circuit board 13 and a penta-band antenna 14. The circuit board 13 has a grounding plane 131. An antenna location region 132 at a side of the grounding plane 131 is for disposing the penta-band antenna 14. As shown in FIG. 1B, the penta-band antenna 14 may be assembled to a nonconductive substrate 15, in order to improve the convenience of fabrication. The penta-band antenna 14 is a single-pole antenna coupled to a feeding terminal F1. The penta-band antenna 14 has a radiating portion 141 and a radiating portion 142. For the conventional third-generation mobile communication, the penta-band antenna 14 of the mobile communication device 1 needs to provide following five operation bands 850 MHz/900 MHz/1800 MHz/1900 MHz and 2100 MHz. However, due to the development of long germ evolution (LTE) technology, the antenna of the mobile communication device needs to afford more operation bands for fitting in with both requirements of the conventional third-generation mobile communication system and the LTE technology.